Close
Ck engine light stays on. what is cause of? been chked..
1999 Mercury Mountaineer

Ck engine light stays on. what is cause of? been chked..

(1999 Mercury Mountaineer)
Check engine light stays on-what is causing this?
2 answers & 0 comments
Popular Answer
If the Check Engine Light/Service Engine Soon light illuminates while you are driving, the car's on board computer sees a fault in the engines management system that is causing an excess amount of pollutants to be emitted from your car. This could result in engine damage if left neglected. Some problems that can cause the Check Engine light to stay on may take two "drive cycles' to complete before illuminating the Check Engine Light. The computer sees a problem and looks for an identical set of circumstances to occur to confirm that it has indeed seen a problem before turning on the light. A Check Engine light that continually flashes while you are driving is serious and is a sign that the computer sees a problem that seriously risks damaging the catalytic converter which may result in an expensive repair or even may cause a fire! Diagnostic codes are stored in the vehicle's computer and can be retrieved using a scantool that communicates with the computer in your car. We have in our Repairpal website an encyclopedia with in depth articles about computer, and computer control systems, emission and driveability problems. http://repairpal.com/check-engine-light
Sign in to reply
Check Engine Light Diagnosis
$88 - $111 Learn More
If the Check Engine Light/Service Engine Soon light illuminates while you are driving, the car's on board computer sees a fault in the engines management system that is causing an excess amount of pollutants to be emitted from your car. This could result in engine damage if left neglected. Some problems that can cause the Check Engine light to stay on may take two "drive cycles' to complete before illuminating the Check Engine Light. The computer sees a problem and looks for an identical set of circumstances to occur to confirm that it has indeed seen a problem before turning on the light. A Check Engine light that continually flashes while you are driving is serious and is a sign that the computer sees a problem that seriously risks damaging the catalytic converter which may result in an expensive repair or even may cause a fire! Diagnostic codes are stored in the vehicle's computer and can be retrieved using a scantool that communicates with the computer in your car. We have in our Repairpal website an encyclopedia with in depth articles about computer, and computer control systems, emission and driveability problems. http://repairpal.com/check-engine-light
Sign in to reply
The computer turns on the light due to reading it is getting from various sensors that are not reading correctly due to age, wiring issues or some unit is failing such as injector or EGR. You need to have the code checked to see what it is.
Sign in to reply

Similar Questions

View answers to similar questions from RepairPal's community of auto experts and enthusiasts.
No start anti theft flashing how do i reset anti theft or how do i reprogram key have 2 keys no key fob keys don't...
2004 mercury mountaineer.replaced starter and battery will not crank up .ranperfect the night before but today will...